Smartphones and other portable electronic devices are typically operated in one of two ways. In some cases the smartphone may be held in front of the head so that the speaker can see the display (i.e., “screen speaking mode”). In noisy environments, however, the user may hold the device close to the head (i.e., “ear-held mode”, e.g. in telephony applications) in order to have the loudspeaker very close to the ear. For controlling speech enhancement algorithms, these are quite different use cases. For example, in screen speaking mode, both microphones may receive the speech signal with similar quality. In contrast, in ear-held mode the microphone on the bottom may exhibit a higher speech level than the microphone on the top of the device. Hence, the top microphone may be used as a noise reference microphone.